聚四氟乙烯与环氧树脂复合浸渍对石墨性能的影响

为探究聚四氟乙烯(PTFE)和环氧树脂(EP)复合浸渍工艺对石墨性能的影响,以PTFE和EP为浸渍剂分别对石墨进行单独浸渍和复合浸渍,测试浸渍石墨的开孔气孔率、增重率以考察浸渍效果,并通过抗压强度测试、热重分析和耐腐蚀失重率测试考察不同浸渍工艺对石墨机械强度、热稳定性和耐腐蚀性的影响。结果表明,PTFE单独浸渍石墨不透性难以达标,且抗压强度较低;EP单独浸渍石墨热稳定性和耐腐蚀性较差;而采用2次PTFE和1次EP复合浸渍的石墨增重率最高(16.750%)且孔隙率最低(1.006%),抗压强度比PTFE单独浸渍石墨高10 MPa,石墨的热稳定性和耐腐蚀性较EP单独浸渍石墨好。     

室温固化高性能胶粘剂的研制

为了改善环氧树脂(EP)胶粘剂对某些金属和非金属材料的粘接性能,采用自制的增韧剂改性EP,制备了一种可室温固化的无溶剂双组分EP胶粘剂。考察了增韧剂用量、不同的室温固化剂及表面处理方法对金属和非金属材料的粘接性能、耐热性能和耐介质性能的影响。实验结果表明,该胶粘剂对金属和非金属都具有良好的粘接性能;用于PVC和ABS粘接时,则被粘材料被破坏;用于聚四氟乙烯(PTFE)和聚乙烯(PE)粘接时,其最高剪切强度分别为1.9 MPa和1.8 MPa。     

纳米材料改性环氧树脂的研究进展

对用于改性环氧树脂(EP)的纳米材料的种类与基本性质,纳米材料在EP中的分散技术以及纳米材料改性EP的机理进行了综述,并对纳米材料改性EP的前景进行了展望。     

炭黑/环氧树脂复合材料阻温特性研究

分别以低结构炭黑(F101)和高结构导电炭黑(XE2)作为导电填料,不同牌号(E-54,E-51和E-44)的环氧树脂(EP)作为基体树脂,采用超声分散溶液混合法制备了炭黑/环氧树脂(CB/EP)复合材料.研究了CB结构、CB含量和EP基体等对复合材料正温度因数(PTC)效应的影响.结果表明:F101/EP复合材料具有...     

氧化石墨烯-水性环氧树脂固化剂的制备及性能

首先，将三乙烯四胺(TETA)和氧化石墨烯(GO)球磨，得到TETA改性GO分散液TGO；然后向其中依次滴加双酚A型环氧树脂E44、三羟甲基丙烷三缩水甘油醚(TPEG)、甲氧基聚氧乙烯-2,3-环氧丙烷(MEH)和γ-(2,3-环氧丙氧基)丙基三甲氧基硅烷(KH560)，采用原位聚合法合成了氧化石墨烯-水性环氧树脂固化剂(TGO-WPEA)；采用上述工艺，不添加GO的条件下制得水性环氧树脂固化剂(WPEA)。将WPEA和TGO-WPEA分别与环氧树脂乳液(Epikote-6520)复合制得水性环氧树脂(EP)和氧化石墨烯改性水性环氧树脂(TGO-EP)防腐涂料。通过FTIR、XPS和XRD对材料进行了结构表征，采用电化学测试和盐雾实验对TGO-EP的防腐性能进行了评价。结果表明，水性环氧树脂固化剂(WPEA)分子通过共价键连接到GO表面，改善了GO在EP中的分散稳定性和接枝率，提高了TGO-EP复合涂料对腐蚀介质的屏蔽性能。与纯EP涂层相比，TGO-EP涂层腐蚀电位从–0.267 V提高到–0.125 V，腐蚀电流密度从5.44×10^–8 A/cm²     

热固性树脂/碳纳米管复合材料的研究进展

介绍了碳纳米管(CNTs)在改性环氧树脂(EP)、酚醛树脂(PF)、双马来酰亚胺树脂(BMI)以及氰酸酯树脂(CE)等热固性树脂方面的应用,综述了EP/CNTs、PF/CNTs、BMI/CNTs、CE/CNTs复合材料的近期研究进展,详细叙述了CNTs对热固性树脂的力学性能、热性能、摩擦性能的改善情况,结合扫描电镜分析结果研究了CNTs在EP和BMI中的分散情况,并指出了热固性树脂/CNTs复合材料存在的问题和应用前景。     

纳米TiO_2改性炭纤维/环氧树脂复合材料性能研究

采用扫描电镜(SEM)、透射电镜(TEM)、X射线光电子能谱(XPS)仪和NOL环等方法,对纳米TiO2在环氧树脂(EP)体系中的分散效果、炭纤维表面状态及复合材料性能等进行了系统研究。结果表明:采用高速剪切与超声波复合分散工艺,可以将纳米TiO2均匀分散在EP体系中;当w(纳米TiO2)=2%～3%时,纳米TiO2/EP浇铸体的最大拉伸强度为112 MPa、最大弯曲强度为175 MPa和最大Tg为141.9℃;纳米TiO2可以有效改善炭纤维与EP基体间的界面结合力,形成较理想的界面相,制成的复合材料具有优异的力学性能,其拉伸强度、拉伸模量和剪切强度分别为2.15 GPa、117 GPa和49.9 MPa。     

石墨烯的分散及其在防腐涂层中的应用

以生物基没食子酸(GA)为原料,在碱性条件下与环氧氯丙烷(ECP)发生环氧化反应,合成了没食子酸基环氧树脂(GEP)。GEP作为石墨烯分散剂,能够将石墨烯稳定地分散在有机溶剂中,其分散浓度高达5 mg/m L,采用TEM和AFM对石墨烯的分散状态和层数进行了表征。将分散后的石墨烯以0.5%的质量分数,添加到双组分环氧树脂涂料中,制备了石墨烯环氧复合涂层(GEP-G0.5/EP)。利用Tafel极化曲线、涂层吸水率和中性盐雾测试对涂层防腐性能进行表征。结果表明:相比于纯环氧涂层,GEP-G0.5/EP涂层的极化电阻和耐盐雾性大大提高,涂层吸水率下降0.22%。     

CTAB对锌-镍合金基复合电镀液中PTFE分散性的影响

针对聚四氟乙烯(PTFE)在镀液中分散难的问题,以分散液中PTFE的润湿效果、Zeta电位以及PTFE的粒径分布为指标,研究了阳离子型表面活性剂十六烷基三甲基溴化铵(CTAB)添加量对PTFE在去离子水中分散性的影响。结果表明,随着CTAB用量的增大,PTFE的分散均匀性和稳定性改善,微米PTFE基本能够实现单分散。CTAB用量大于PTFE质量的3%后,PTFE在10 min内可被完全润湿。镀液中CTAB用量为3%时,可复合电沉积得到PTFE均匀分布的Zn–Ni–PTFE复合镀层,但需持续搅拌镀液,以确保PTFE均匀分散。     

纳米Al_2O_3粉末改善环氧树脂耐磨性的研究

进行了利用纳米氧化铝 (α -Al2 O3 和γ -Al2 O3 )改善环氧树脂耐磨性能的研究。利用超声分散法将纳米氧化铝粉末加入环氧树脂之中 ,利用磨损失重法评价了环氧树脂复合材料的耐磨性能 ,通过扫描电镜观察了纳米粉末在环氧树脂中的分散情况 ,尝试解释了纳米氧化铝提高环氧树脂耐磨性能的机理 ,并确定了较优的纳米氧化铝添加量。试验表明 ,填充纳米氧化铝粉末可以提高环氧树脂的耐磨性能。较优的配方为EP (E - 5 1) 1份 ,PA6 5 10 7份 ,KH - 5 5 0 0 0 4份 ,30～ 6 0nmγ -Al2 O3 0 1份。     

聚砜改性环氧树脂复合材料热老化性能研究

以聚砜(PSF)改性环氧树脂(EP)为基体树脂,玻璃纤维为增强材料,采用高温模压成型法制备出PSF改性EP/玻璃纤维复合材料。结果表明:PSF能有效提高EP基体的热稳定性能;经200℃热老化72 h后,PSF改性EP/玻璃纤维复合材料的热失重率<1%,其冲击强度和弯曲强度呈先升后降态势,电绝缘性能仍然较好(其体积电阻率和表面电阻率的数量级仍保持在1012左右);该复合材料在高温绝缘场合中具有良好的应用前景。     

环氧树脂对聚对苯二甲酸丁二酯共混物的增韧增强研究

利用环氧树脂(EP)与聚对苯二甲酸丁二醇酯(PBT)的相容性,考察了EP对共混物PBT/ABS-gGMA性能的影响。采用动态力学分析仪(DMA)、旋转流变仪、Haake流变仪和扫描电镜(SEM)研究共混物的性能。DMA、DSC和旋转流变仪的测试结果表明PBT与EP是相容的;流变性能测试结果表明EP对PBT/ABS-g-GMA共混体系起到增容作用;SEM观察结果发现少量的EP加入对共混物的相形态没有明显影响,分散相在PBT基体中均匀、稳定分散,而过量的EP使共混物中出现一些较大的相区,分散相发生团聚;力学性能测试结果表明适量的EP就能明显提高共混物的冲击性能,而过量的EP又会使共混物的冲击强度下降。     

MBS对CPVC凝胶化的影响及CPVC/MBS共混物性能的研究

采用差示扫描量热仪和HAAKE流变仪研究了甲基丙烯酸甲酯-丁二烯-苯乙烯共聚物(MBS)对氯化聚氯乙烯（CPVC）凝胶化性能及流变性能的影响,并对CPVC/MBS共混物的力学性能、耐热性能、微观形貌进行了系统研究。结果表明,MBS能改善CPVC的加工性能。随着MBS含量的增加,共混物的凝胶化度得到极大的提高,塑化时间明显缩短,平衡扭矩不断上升,平衡温度大幅上升。MBS用量为6份时,CPVC/MBS共混物的综合性能最佳。     

Synthesis of poly(tetrafluoroethylene)/poly(butadiene) core-shell particles and their graft copolymerization

This article describes how to convert the unreactive surface of poly(tetrafluoroethylene) (PTFE) into poly(styrene-co-acrylonitrile) (SAN). Composite particles with a crosslinked poly(butadiene) (PB) shell covered over a PTFE core were prepared by an emulsifier-free seeded emulsion polymerization of butadiene in the presence of PTFE latex. It was found that the increase in the PB crosslink density resulted in depressing the formation of PB secondary particles. Then, styrene and acrylonitrile were able to graft onto PB shell in high efficiency of 70%. SAN-modified PTFE/PB core-shell particles could eventually be dispersed homogeneously in a SAN matrix. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:185–190, 1998     

Study on preparation and anticorrosive performance of a new high hydrophobic anticorrosive coating

Water-based anticorrosive coatings have poor water resistance, which easily lead to coating deterioration and metal corrosion. In order to improve the anticorrosion performance of waterborne coating, herein, the polytetrafluoroethylene/dimethyl siloxane/epoxy resin (PTFE/PDMS/EP) hydrophobic anticorrosive coating was prepared by layer-by-layer construction. The spatial structure and microscopic morphology of the hydrophobic coating were analyzed by XRD, FTIR, and SEM. The hydrophobicity and corrosion resistance of the composite coating were analyzed by hydrophobicity test, electrochemical polarization curve, hydrophobicity and corrosion resistance test of the mixed layer, Tafel polarization curves, and AC impedance spectrum. The results showed that the water contact angle of PTFE/PDMS/EP coating reached 141° and the protection efficiency of PTFE/PDMS/EP coating was 98.62%. After soaking for 7 days, the corrosion process still stays at the initial stage, which was mainly due to the good sealing and barrier properties and high anticorrosion efficiency of PTFE/PDMS/EP coating. The coating has high corrosion protection efficiency and long service life, which is of great significance to metal corrosion protection in harsh marine environments.     

Preparation of chlorinated poly(vinyl chloride)‐g‐poly(N‐vinyl‐2‐pyrrolidinone) membranes and their water permeation properties

Chlorinated poly(vinyl chloride) (CPVC) membranes for microfiltration processes were prepared with the combined process of a solvent evaporation technique and the water‐vapor induced‐phase‐inversion method. CPVC membranes with a mean pore size of 0.7 μm were very hydrophobic. These membranes were subjected to surface modification by ultraviolet (UV)‐assisted graft polymerization with N‐vinyl‐2‐pyrrolidinone (NVP) to increase their surface wettability and decrease their adsorptive fouling. The grafting yields of the modified membranes were controlled by alteration of UV irradiation time and NVP monomer concentration. The changes in chemical structure between the CPVC membrane and the CPVC‐g‐poly(N‐vinyl‐2‐pyrrolidinone) membrane and the variation of the topologies of the modified PVC membranes were characterized by Fourier transform infrared spectroscopy, gel permeation chromatography, and field emission scanning electron microscopy. According to the results, the graft yield of the modified CPVC membrane reached a maximum at 5 min of UV exposure time and 20 vol % NVP concentration. The filtration behavior of these membranes was investigated with deionized water by a crossflow filtration measurement. The surface hydrophilicity and roughness were easily changed by the grafting of NVP on the surface of the CPVC membrane through a simultaneous irradiation grafting method by UV irradiation. To confirm the effect of grafting for filtration, we compared the unmodified and modified CPVC membranes with respect to their deionized water permeation by using crossflow filtration methods. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3188–3195, 2003     

CR/CPVC/MMA三元接枝共聚物

研究了高氯含量的氯化聚氯乙烯（CPVC）对氯丁橡胶／甲基丙烯酸甲酯接枝共聚合的影响,用红外光谱法和差热分析法对改性粘合剂进行了表征,结果表明,使用CPVC不仅明显提高粘合剂PVC材料的粘接强,而且还降低了成本。     

聚四氟乙烯泡沫材料的成型工艺

介绍了聚四氟乙烯（ＰＴＦＥ）泡沫材料的成型工艺，以悬浮聚四氟乙烯为原料，选用稠环芳烃作成孔剂。混合后进行预成型，将预成型产品进行烧结，烧结的起始阶段为干燥，使成孔剂逸出，然后进入再烧结阶段，可按不同配比制出不同介电常数的泡沫材料以满足各使用要求。     

超支化聚合物改性环氧树脂固化体系力学性能研究

研究了羟端基脂肪族超支化聚酯(HBPE)对环氧树脂(EP)固化体系力学性能的影响。结果表明,加入较低含量的HBPE就能较好地改善体系的拉伸强度和冲击强度,同时对拉伸弹性模量的影响不大。其中,第三代和第四代HBPE的质量分数为3%时,固化体系的拉伸强度分别提高20.54%和18.64%,断裂伸长率分别提高41.02%和58.66%,冲击强度分别提高71.14%和117.36%。对固化体系的拉伸断面进行了分析,发现引入HBPE后,材料表现出韧性断裂;HBPE以微分散相的形式均匀分散在EP基体中。     

低黏度耐超低温室温固化环氧树脂密封剂

以四氢邻苯二甲酸二缩水甘油酯[711EP(环氧树脂)]为基体、二乙二醇缩水甘油醚(JX-023)为柔性改性剂和二乙烯三胺(DETA)为固化剂,制备可室温(25℃)固化的高性能EP密封剂,并采用单因素试验法优选出制备EP密封剂的最优配方。研究结果表明:当m(711EP)∶m(JX-023)∶m(DETA)=1∶1∶3时,EP密封剂的室温综合性能相对最好;其低温(-196℃)剪切强度(16.5 MPa)和低温剥离强度(31.2 kN/m)接近于室温性能,同时其耐高低温(-196～100℃)循环性能优异,初始黏度低于0.1 Pa.s;该EP密封剂可用于超低温领域及微小部件的粘接与密封。